And I've created myself a warm-up:
A few minutes of Balance Training( example here)
30-60 Jumping Jacks
20-40 Mountain Climbers
A few minutes of boxing
5-10 rounds of Day 1 of my current level, with focus on good form
5-10 slow repetitions of the exercise I think I could improve most at(currently squats)

Planned to do L3D1 today, but instead trained with a friend.
Did about 20 minutes of boxing, then we did pull-ups in ladder style (Works like this: Everyone does one pull-up, then everyone does two pull-ups, and so on until one isn't able to complete all repetitions. Then it goes back down to one pull-up, if still possible. Managed 5 full repetitions. When done in non-ladder style my pull-up maximum is about 8)